Levels of Insecticide Resistance in Fresh-water Shrimp, Palaemonetes kadiakensis

Abstract

In 24-hr bioassays, fresh-water shrimp, Palaemonetes kadiakensis, from 3 areas of intensive pesticide use in the Mississippi delta were 1 to 25 times more resistant to 7 organochlorine, 3 organophosphorus, and 1 carbamate insecticides than shrimp from Noxubee National Wildlife Refuge (Bluff Lake). Although populations differed in amount of resistance, the relative toxicity of the insecticides was similar. Toxicity of the insecticides, ranked in descending order, was as follows: Most toxic, endrin, DDT, methyl parathion, parathion; medium toxicity, Guthion, lindane, toxaphene, Strobane; least toxic, chlordane, Sevin, and heptachlor. When caged in a canal near cotton fields, susceptible shrimp suffered 66% more mortality than did native, resistant shrimp.